This invention relates generally to the art of fabricating concrete piers in the earth; more particularly, the invention relates to a support which is adapted to be affixed to a steel reinforcing cage for the purpose of fostering the lowering of the cage into a pier hole--just prior to the time that concrete is poured into the hole.
This particular invention is related to another invention which is disclosed in co-pending U.S. application Ser. No. 778,975 entitled "Sled For A Reinforcing Cage Used In A Pier," now U.S. Pat. No. 4,627,211 issued Dec. 9, 1986.
As described in the aforementioned patent, it is well known to reinforce concrete piers and other concrete structures with steel reinforcing rods that are tied together to form what is called a cage. And it is also known to provide spacers in order to hold such reinforcing rods (or equivalent steel mesh) away from the sides of concrete forms. Examples of such spacers of the prior art are shown in the following: U.S. Pat. No. 790,230 to Stemple entitled "Method of Protecting Piles Or The Like"; No. 1,708,277 to Martin entitled "Device For Positioning The Reenforcement Of Concrete Structures"; No. 3,722,164 to Schmidgall entitled "Spring Wire Spacer, Especially For Spacing Reenforcing Mesh From the Form In The Manufacture Of Concrete Structures And The Like"; No. 3,257,767 to Lassy entitled "Snap-On Spacer Positioner For Reinforcement"; and No. 3,471,986 to Swenson entitled "Spacer For Reinforcing Mesh For Concrete Pipe And The Like."
The invention disclosed in my earlier patent provided definite advantages over the bent wire or bent sheet-metal spacers of the prior art; and the plastic runner provided a definite advantage in that there was no threat to the integrity of a steel reinforcing cage which could be created by the oxidation (rusting) of a spacer. However, there are still some persons who are so cautious and so conservative as to be apprehensive about the durability of even polypropylene in a long-term situation. For those persons who expect a pier to endure and carry loads for a period of 100 years or more, any construction material which has characteristics different from concrete is perhaps suspect. To satisfy those persons who would like the exterior surface of a pier to be 100% concrete, a construction is disclosed herein which can function as an effective spacer or sled, and which can be molded out of concrete. If the spacers or sleds are molded from concrete and then attached to a reinforcing cage before wet concrete is poured around the cage and into the pier hole, then the resulting exterior surface of the pier will be 100% cementitious. With the primary material of the pier and the spacers of this invention having essentially the same coefficient of thermal expansion, etc., there is no opportunity for any environmental condition to later contribute to any structural defect. It is therefore an object of this invention to teach a construction for a pier sled that can be molded from a cementitious material.
It is another object of this invention to provide a pier spacer having integrally molded tie wires which are so firmly embedded in the spacer as to absolutely preclude any accidental tear-out during installation of the spacers of use thereof.
Another object of this invention is to provide an extremely strong but lightweight spacer which can function like a sled in fostering the descent of a reinforcing cage into a pier hole--without doing untoward damage to the sides of the pier hole.
Still another object of the invention is to provide a spacer having integral tie wires which are positioned at the most advantageous locations for achieving a secure installation alongside a reinforcing cage, such that a tie wire does not become accidentally misplaced or omitted.
These and other objects will be apparent from a careful study of the specification provided herewith and the attached drawing to which it refers.